2.20 The Evolution of the Technology of Polychrome Sculptures in the Baroque/Rococo Period in Minas Gerais, Brazil

Project AbstractThe captaincy of Minas Gerais, in southeastern Brazil, is located
in a region of mountains. It had practically no significance for
the Portuguese Crown until the end of the seventeenth century, when
pioneer expeditions from the coast, looking for gold, found it in
these rivers and mountains.

Following the discovery of gold, the region suddenly experienced
a population explosion, and was subjected to strong Portuguese political
control. Religious orders and missionary activities were forbidden
to develop in Minas Gerais, where the gold was found. This restraint
led to the development of third orders of laymen and brotherhoods,
which took charge of constructing several Roman Catholic churches
in many different areas. The richness of the decoration in the interior
of these churches was based on baroque esthetics.

The objective of this research project was to perform a detailed
material and technological study of the polychromed sculptures in
Minas Gerais, e.g., pigments, binding media, varnishes, glazes,
gilding, and silvering, through physicochemical methods of analysis.
The project was the experimental part of the Ph.D. in chemistry
of L. Souza, working under the supervision of D. Stulik. The researchers
brought from Brazil about 550 small samples of sculpture's polychromies,
400 from several sculptures of various museums and cities in Minas
Gerais, and 150 from the retables of the Mother Church of Our Lady
of Conception, in Catas Altas, Minas Gerais.

The Mother Church of Our Lady of Conception in Catas Altas, Minas
Gerais (Brazil), is a magnificent example of the collaborative construction
of art monuments by Portuguese and indigenous people. The remarkable
fact about this church is that the architectural construction is
finished but the internal decoration is not. The unfinished interior
allowed us to document and study the different steps for the building
up of carving and sculptural works. In the ceiling and also the
side altars, there are parts showing just the carved wood, others
presenting the wood with the ground, and other parts completely
polychromed and finished, showing sgrafitto, gilding, silvering
and glazes, etc.

Souza, L. A. C., A. R. Ramos, and C. Avila, "The Mother Church
of our Lady of Conception, Minas Gerais, Brazil-The Unfinished Story,"
Poster presented at the IIC-Conservation of the Iberian and Latin
American Cultural Heritage, Madrid, September 9-12, 1992.

ABSTRACT-The region of gold deposits in Brazil was discovered by
pioneers at the end of the seventeenth century. The richness and
the demographic explosion of the new General Mines region (Minas
Gerais) gave rise to strong Portuguese political control: religious
orders and missionary activities were forbidden there. Consequently,
Minas Gerais saw the development of Third Orders and brotherhoods
of laymen. The competition between the various religious groups
prompted the construction of many churches, the richness of their
interior decoration based on the baroque aesthetic. The mother church
of Nossa Senhora de Conceição in Catas Altas is a
magnificent example of the contribution of both the Portuguese and
the indigenous people to the construction of artistic monuments.
The church dates from 1738 and the architectural construction is
complete but the internal decoration remains unfinished. This made
it possible to study the techniques and materials used. In the areas
where the ground has been applied but no polychromy, there is a
first layer of kaolin followed by a gesso layer. This unusual technique
may have been prompted by economy: kaolin is a mineral easily found
in the metallurgical zone of Minas Gerais.

Souza, L., "Technology of Colonial Polychrome Sculptures in Brazil,"
Presentation at the Scientific Program Research Conference, The
Getty Conservation Institute, December 16-17, 1992.

ABSTRACT-None available.

Souza, L., "Conservation of Baroque Art in Minas Gerais, Brazil,"
Presentation at the UCLA Program on Brazil, UCLA Latin American
Center, University of California, Los Angeles, February 2, 1993.

ABSTRACT-Discussion on the efforts to retrieve technologies used
in the creation of art in the 18th century, and their application
to restoration in the 20th century.

ABSTRACT-Presents some of the recent findings concerning the use
of glazes on gilding and silvering surfaces of wooden polychromed
sculptures. These preliminary results are part of a major research
project designed to study the evolution of the technology of baroque
and rococo polychromed sculptures in Minas Gerais. The methodology
includes historic research and scientific analytical techniques
such as FTIR, PLM, UV/VIS spectroscopy, SEM, and GC/MS in order
to identify the materials and techniques used in Minas during the
eighteenth century. The focus of study is primarily on the Mother
Church of Our Lady of Conception in Catas Altas, Minas Gerais, because
its internal decoration is incomplete and the church has never been
restored, allowing access to all original materials and techniques
dating back to 1738.

ABSTRACT - Traditional western techniques for gilding of polychrome
sculptures and panel paintings include the use of grounds prepared
by the application of a first layer of gesso grosso followed by
a gesso sottile layer, as described by Cennino Cennini in his treatise
on painting techniques. These techniques were used in Italy since
the middle ages, and were later adopted by many artists in the new
world in the regions under Spanish and Portuguese (Brazil) rule,
sometimes with local variations in the materials and techniques.

This paper discusses the use of FT-IR spectroscopy for the identification
of inorganic materials present in the grounds of baroque wooden
polychromed sculptures from Minas Gerais, Brazil. This technique
allows the quantitative analysis of the separate layers of the grounds,
with respect to the anhydrite/gypsum ratio present in the sample.
The techniques has several advantages over the one currently used
(Debye-Scherrer chamber for powder X-Ray diffraction). FT-IR spectra
can be obtained in a few minutes allowing quantitative quantitative
results, while XRD usually takes more time and does not give accurate
data for quantitative studies. The paper also discusses the results
of the studies of the grounds in Brazilian polychromed sculptures
and compares the original Italian technique with Portuguese and
Spanish techniques and its variations in Brazil.